Been having some REALLY strange cramps lately?

For maybe 3 days now...they happen a lot when i lie down. They only come on one side; but of course, I only have one ovary, so thats another factor to consider. They are very sudden and not so much as excruciating but just extremely uncomfortable. It feels like my organs are flipping around. My period is also 2 days late, but I got negative results from an hpt. I took clomid at the beginning of this cycle. Anyone have any idea what could be going on, or experienced something similar?